Discharge tube adapted for generating oscillations



May 16, 1950 c. VERBURG ETAL DISCHARGE TUBE ADAPTED FOR GENERATING OSCILLATIONS 2 Sheets-Sheet 1 Filed April 18, 1946 INVENTORS.

ATTOEMZ May 16, 1950 c. VERBURG ETAL DISCHARGE TUBE ADAPTED FOR GENERATING OSCILLATIONS Filed April 18, 1946 2 Sheets-Sheet 2 m m m m Patented May 16, 1950 DISCHARGE TUBE ADAPTED FOR GENERATING OSCILLATIONS CornelisVerburgEdnard Gerardus Dorg elo, and Frans MichelPenning, Eindhoven, Netherlands, assignors, by mesneassignments, .to Hartford- National Bank and Trust Company, Hartford,

Conn, as trustee Apnlication April 18, 1946,"Serial No. 662,972 I In the Netherlands November 27, 1941 section .1, Piiblic Law 690, August s, 1946 Patent expires November 27, 1961.,

1': Claims: (01.315-51- This" invention relates to a discharge tube adapted for generating oscillations of preferably ultra-high freduency, -in which an electron beam isfproducedand led successively-along a velocity control "electrode 'system constituted by at least threeelectrodes; ardrift space electrode and a second elect-rode -system' also constituted "by at least three; electrodes? The "present invention has for its'purpo'seto' provide a form of fconstruction of such a dis'-' charge tube, iriwhich a symmetrical arrangement of the electrode systems isensuredi' Accordingto the inyentiom this object is atta'ined by that the remote outer electrodes of the electrode systerfnsare each" connected;'to the wall of -facylindrical drum; whoselaxis is parallel to theaxis of "the discharge "tube; said drums constitiiting' the oute'r conductors of those parts of the feedback line which are contiguous to the Figs. Za'and 2b 'are'cross sectional views taken on'i the line 1 II II of the. device I shown in Fig-f 1, Figzf' 21)." being an alternate embodiment of. the structurershownzin Fig; 2a, and i Figs: '3, 4aand 'i5' show other constructional examples iof'rthe deyiceta'ccording fto' the invention.;;

The device show-n inFigml-corn'prises an envelope I of .gla'ss-or--;q1.-iartz, containing an electrode system" for producing; an electron beam which is constituted by an indirectly heated cathode 2,-a grid- 3 and an accelerating electrode a, the last-mentioned electrode having applied to it a voltage which is;.-positive relatively ;to the oath: ode z. At the end Which'iSTemO-te fromithe' said electrode system; thesenvelope: 1, contains =fa collectorelectrode-t andanselectrode l which serves to',,-catchtithev primary electrons which may be re' flected by theelectrode 6 andtheemittedsecond r-elect o s; w

On he' r om em -modem the: c lector electrode'fi; the ,electron emitte'dsb --thecathode 2 are'led a on 1atea e wo eletrcde seems.

of which the first, the velocity control electrode system, is constituted by three electrodes, name control electrode 8 and two bounding electrodes 9 and Ill. The bounding electrode lll co stituted by an extremity of the drift-space el'e'ctrode I I which constitutes a so-called drift-space through which the electron beam is led afterh'a vi ing passed the control-electrode systems cusse quently, the electron beam is led along the Serena: electrode system which-is also constituted by'thre'e": electrodes, namely, electrode 12 and two bounding? electrodes I3 and I4, of which the latter iscon stituted by that extremity of the drift-space electrode I I which is remote from'the velocity control electrode system.

For generating oscillations, the second' electrode system I2, I3, I4 is connected to the velocity? control electrode system through the-intermediaryofa feedback line. v

The operation of the described discharge' tiib' as a device for generating oscillations willno't b described, since it may be assumed as known. The invention relates to the constructional at" rangement of the discharge tube and'inor'e'particularly of the feedback line which connectsth'l, electrode systems 8; 9, H) and I2, 13, Ill" e,1"i'ci1 together with these electrode systems, constitutes the oscillatory system, which determines the fre quency'of the oscillationsto be generated.

According to the invention, the outer 'con ff ductor of that part of the feedback line which: is connected to the electrode systems 3,9, Ill I2; I3, Hi is consituted by two cylindrical drums; of which the axes coincide with, or are "at" least parallel to the axis of the discharge tube "and joi which the remote walls i5 and IE are connected respectively to the remote outer electrodes!) and I3 of the two electrode systems. Theadjac' ent' walls I1 and E3 in the present form of constriz'c-g tion are connected to theadjacent outer elec'; trodes it-and "It 'ofnthe electrode systems; The, circularsurfaces of the drums are designated 9." andZfl respectively. The-two drums are Jc nected by means of a cylindrical conductor, which constitutes .the outer. conductor offlth re maining part preferablyco-axial, of the feed? back line. The inner conductor of the feed-back. line, :whichextendsbetween the circular suria I9 and 20 of the two drums and connectstheinn electrodes 8 and, i2, is designated ,22 ane -may also be constituted by a tubular conductor;

The drums i5, I1, 19 and i5, IS, 20 are supported by the tube wall by means of local re-entrant parts 23 which are engaged by mica supporting discs 24 and 25 which are forced against the walls 15 and [6 of the drums by means of discs 26 and 21 respectively. The shape of the mica discs is such that the whole oscillatory system, which is constituted by the two electrode systems 8, 9, l and l2, l3, l4 and the feedback line, may be shoved into the envelope l, beyond the re-entrant parts 23, into the correct position, whereafter by means of a slight rotation of the whole system the mica discs may be caused to engage the re-entrant parts 23, thus supporting the whole back-coupled system. 1

A supply-conductor 28 is connected to the circular surface I9 of the drum 15, H, is for the purpose of applying to the electrodes 8 to it a high positive voltage relatively tothe cathode.

Figs. 2a and 2b, which are cross-sectional views taken on the line 2a2a of the discharge tube represented in Fig. 1, show in what manner the energy of the oscillatory system which is constituted by the electrodes in to Hi and the feedback line may be abstracted. The energy is abstracted from the central electrode 12 of the second electrode system by means of a conductor 29 which is movably arranged in a re-entrant part of the tube wall which is of non-conductive material and capacitatively coupled to the electrode #2. The wall 30 of the reentrant part is made, preferably at-least in part, of glass or quartz. Further, the energy abstracting conductor 29, which may also serve as an aerial for emitting the generated oscillations, is preferably normal to the circular surface 20 of the cylindrical drum l6, I3, 20.

.It is also possible for the energy abstracting conductor 28 to be arranged within the tube wall, in which case the tube wall has to be provided with a protuberance of glass or quartz 30. which is indicated at 29' in Fig. 2a. In this case magnetic means may be used for the adjustment of the conductor 29', which is slidably supported within protuberance 30' by means of spacers 29".

---When the conductor 29 (or 29) is displaced, the capacitative coupling of the conductor 29 with the electrode l2 varies and this results in the energy abstracted from the oscillatory system being also varied. Further, it has been found that it also depends on the spacing between the conductor 29 and the electrode 12, which of the difierent frequencies which are determined by the dimensions of the oscillatory system constituted by the electrode systems-8,9, l0 and l2, l3, hi and the feedback line, will occur so that a variation of the spacing may bring about a discontinuous variation in frequency.

. .In the form of construction shown in Figs. 1 and 2, the baclr-coupledsystem is completely surrounded by a glass envelope. However, as is shown in the forms of construction of Figs. 3 and 4, it is also possible to shape the electrode I3into the form of a hollow conductor closed at the end which is remote from the drift-space electrode H, which conductor constitutes the wall of the tube and of which that extremity which is remote from the wall [6 serves as a collector electrode.

Fig. 3 shows a simplified form of construction of the discharge tube according to the invention represented in Figs. 1 and 2. The simplification consists in the construction of that part of the feed-back line which connects the two drums l5, l1, l9 and l6, I8, 20. In this form of construction, the outer conductor of the said part of 1 which may serve, in addition, as an aerial the feedback line is constituted by the inner surface of a bore in a solid, conductive, cylin drical body 3| which has the same diameter as the drums and is arranged co-axially thereof. In this case the drift-space electrode II is constituted by the inner surface of a second bore in the said body 3|, while the end surfaces of the body 3! constitute the adjacent walls, connected to the electrodes I0 and I4, of the cylindrical drums of which the walls l5 and it are connected respectively to the remote outer electrodes 9 and I3. Another feature of the form of construction shown in Fig. 3 consists in that the circular surfaces i9 and 20 of the cylindrical drums and of the body 3! form apart of the tube wall, while the remote outer electrodes 9 and 13 of the electrode systems 8, 9, If! and l2, l3, 14 have sealed to them parts of the tube wall which are made of glass or quartz. Further, in this form of construction, the oscillations generated in the oscillatory system constituted by the electrode systems 8, Si, l0 and l2, l3, l4 and the feedback line are derived from this system by abstracting energy from the electronic beam by means of a resonator, for example a cavity resonator 32 which is constituted by a cylindrical drum whose axis coincides with, or is at least parallel to the axis of the discharge tube. In this drum the opposite walls 33 and 34 are provided with apertures which are opposite to each other in the direction of the electron beam and are passed by the latter; The electron beam, whose intensity varies in the rhythm of the generated oscillations, generatesoscillations in the resonator 32 on passing the latter, of which oscillations the frequency issystem. For adjusting the natural frequency of the resonator, the spacing between the wall 33 and the screw 36, and hence the capacity of the resonator may be varied by means of a screw 36.

The oscillations generated in the resonator may be supplied to a load circuit by means of a coupling loop 35 or in any other manner.

In order to avoid excessive heating of that part of the tube wall which is located inside the cavity resonator, use may be made of air-cooling for this part of the tube wall. The cooling air may be blown through an aperture into the resonator and passes out along the gaps which exist between the tube wall to be cooled and the resonator, as is shown by arrows in the figure.

Excessive heating at the place of the collector electrode 6 is preferably avoided by utilizing a water-cooled collector electrode. The cooling jacket is designated 3'! and is traversed by cooling liquid in the direction indicated by arrows.

The discharge tube shown in Fig. 4 corresponds substantially to that shown in Fig. 3.

The difference only consists in that the resonator 32' and the collector electrode 6 form a part of the tube wall and the distance between the middle of the wall 33' of the resonator and that of the wall 34, which is made flexible, is adjustable. The adjustment is effected by means of screws 38. On displacing these screws a wall 39 secured to the collector electrode 6 is displaced and, in addition to the wall 39, the collector electrode 6' and the middle of the flexible wall 34 of the resonator. Furthermore, the discharge tube shown in Fig. 4 comprises energy abstracting conductor 40 and is inductively coupled to the resonator 32'.

In the form of construction shown in Fig. 5,

5 theouter conductor 2| of the feedback line is solely constituted by the cylindrical drums l5, i1", 21 and i6, 18, El which for this purpose nave a side wall ll, [8 in common, This side wall, which corresponds to the side walls I1. and it of the drums in the other figures, is connected to the middle of the drift-space electrode H. For the purposeof obtaining a symmetrical arrangement, the remote outer electrodes 9' and 13" in this form of construction have a length which is approximately equal to half the length or} the drift-space electrode II. Furthermore, asalready mentioned before, the electrode 13 is shaped into the form of a cylirl der' closed at the end which is remote from the drift-space electrode H, which cylinder constitutes a part of the tube Wall and of which that end which is remote from the wall It serves a collector electrode. f We claim:

An electron discharge tube comprising in the order indicated means to generate an electron beam, a first: cavity resonator, a velocity-control electrode assembly in said first cavity resonator,

a second cavity resonator, a secorld electrode assembly in said second cavity resonator, a drift electrode member coupling said assemblies to gether, said velocity control and second electrode assemblies each comprising a bounding electrode. an end portion of said drift electrode member and a central electrode interposed between said bounding electrode and the respective end portion of said, drift electrode member, said assemblies and said member being adjacent the path of said electron beam, and a, transmission line coupling said velocity-control electrode assembly to aid second electrode assembly, said transmission line comprising an outer tubular conductor and an inner conductor Within said outer tubularcom ductor, said inner conductor being coupled at each end to the central electrode of'the respective electrode assembly, said first and said second cavity resonators comprisingcylindrical drums having axes parallel to the axis of said drift electrode member and constituting the outercon- 1 duc to'r of those portions of said transmission line contiguous to said drums.

'2. An electron discharge tube as clainied. in claim 1 wherein said cavity resonators have wall portions in common and the outer conductor of said transmission line is constituted by the cylindrical surface of an a erture in said common "Wall portions through which the inner conductor of said transmission line passes. V 3; An electron discharge tube as claimed in "claim 1 comprising a solid, cylindrical, conductiiig member having an outer diameter equal to the outer diameter of said drum and being co- "a-Srially interposed between said drums, and the outer'condiictor of said transmission line-is con- 'stituted by the cylindrical surface of a bore in saidsolid member connecting said cavity resonators.

4'.- An electron discharge tube as claimed in iclaim 1 comprisin a solid, cylindrical, conducting member havin an: outer diameter equal to the outer diameter of said drum and being coaxially' interposed between. said drinns, the outer conductor of said transmission line being constituted by the cylindrical surface of a first bore in-said solid member connecting said cavity resonators, and" said drift electrode member being constituted by a second bore in saiid'sol-ld member connecting said cavity resonators.

electron discharge tube for generatingv iii oscillations comprising, an envelope, means to generate an electron beam, a first cavity resonator, a velocity-control electrode assembly in said first cavity resonator, a second cavity resonator, a second electrode assembly in said sec- 0nd cavity resonator, a drift electrode member interposed between and coupling said velocity control electrode and said second electrode assemblies, a third cavity resonator, a third electrode assembly in said third cavity resonator, said velocity-control and second electrode as semblies each comprising a bounding electrode, an end portion of said drift electrode member and a central electrode interposed between said bounding electrode and the respective end por tion of said drift electrode member, said third electrode assembly comprising two bounding electrodes in opposing walls of said third cavity resonator, a transmission line coupling said velocity-control electrode assembly to said second electrode assembly, said transmission line comprising a tubular conductor and another conductor within said tubular conductor, said first and second cavity resonators comprising a portion of said envelope, said first, said second and said third cavity resonators being adjacent the path of said electron beam, and output electrode means in said third cavity resonator.

6. An electron discharge tube comprising in the order indicated means to generate an electron beam, a first cavity resonator, a second cavity resonator and a third cavity resonator adjacent the jath of' said electron beam, a velocitycontrol electrode assembly in said first cavity resonator, a second electrode assembly in said second cavity resonator, a drift electrode member cou ling said assemblies together, said velocity-control and second electrode assemblies each comprising a bounding electrode, an end portion of said drift electrode member and a central electrode interposed between said boundirig electrode and the respective end portion of said drift electrode member, and a transmission line coupling said velocity-control electrode assembly to said second electrode assembly, said transmission line comprising an outer tubular conductor and an inner conductor Within said outer tubular conductor, said inner conductor being coupled at each end to the central electrode of the respective electrode assembly, said first and said second cavity resonators comprising cllindrical drums having axes parallel to the axis of said drift electrode member and cons'tituting the outer conductor of those portions of a said transmission line contiguous to said drums,

said third cavity resonator having apertures in opposing walls through which path of said electron beam passes.

7. An electron discharge tube as claimed in claim 6' wherein said third cavity resonator comprises acylindrical drum having an axis parallel to the axis of said drift electrode member and having an end portion adjustable in the direction of said axis.

8. An electron discharge tube for generating oscillations comprising, in the order indicated ahcater; a cathode, a grid, an accelerating electrode, a first cavity resonator, a velocity-control electrode assembly in said first cavity resonator, a secondcavity resonator, a second electrode asseinbly in said second cavity resonator, a drift electrode member interposed between and coupling said velocity-control electrode and, Said second electrode assemblies together, said velocityacontrol and second electrode assemblies. each comprising a bounding electrode, an end portion of said drift electrode member and a central electrode interposed between said bounding electrode and the respective end portion of said drift electrode member, said first and said second cavity resonators being constituted by a hollow cylindrical member having two end walls having central apertures in which the bounding electrodes are positioned and a central wall having a first aperture in which said drift electrode member is positioned and a second aperture through which a tubular conductor passes, said tubular conductor connecting the central electrodes of said electrode assemblies to couple said cavity resonators, said assemblies and said member being adjacent the path of said electron beam, and the bounding electrode of said second electrode assembly constituting the collector electrode.

9. An electron discharge tube for generatin oscillations comprising, an envelope and within said envelope, a heater, a cathode, a grid, an accelerating electrode, a further electrode, a collector electrode, a first cavity resonator, a velocity-control electrode assembly in said first cavity resonator, a second cavity resonator, a second electrode assembly in said second cavity resonator, a drift electrode member interposed between and coupling said velocity-control electrode and said second electrode assemblies together, the axis of said drift electrode member coinciding with the axis determined by said cathode and said collector electrode, said velocity-control and second electrode assemblies each comprising a bounding electrode, an end portion of said drift electrode member and a central electrode interposed between said boundin electrode and the respective end portion of said drift electrode member, said cavity resonators being mounted within said envelope and being interposed between said accelerating electrode and said further electrode, a transmission line coupling said velocity-control electrode assembly to said second electrode assembly, said transmission line comprising a tubular conductor and another conductor within said tubular conductor, said inner conductor being coupled at each end to the central electrode of the respective electrode assemblies, said first and said second cavity resonators comprising cylindrical drums having axes parallel to the axis of said drift electrode member, the outer conductor of said transmission line terminating in said drums.

10. An electron discharge tube as claimed in .claim 9 in which said envelope is provided with a re-entrant portion adjacent the central electrode of one of said electrode assemblies.

11. An electron discharge tube as claimed in claim 9 in which said envelope is provided with a protuberance adjacent the central electrode of one of said electrode assemblies and comprising an adjustable conductor capacitively coupled to said central electrode and mounted in said protuberance.

12. Apparatus comprising an electron discharge tube as claimed in claim 29 in which said envelope is provided with a re-entrant portion adjacent the central electrode of one of said electrode assemblies and having an adjustable conductor capacitively coupled to said central electrode and positioned in said re-entrant portion.

13. An electron discharge tube for generating oscillations comprising, an envelope, means to generate an electron beam, a first cavity resonator, a velocity-control electrode assembly in said first cavity resonator, a second cavity resonator, a second electrode assembly in said second cavity resonator, a drift electrode member interposed between and coupling said velocitycontrol electrode and said second electrode assemblies together, a third cavity resonator, a

third electrode assembly arranged in said third cavity resonator, said velocity-control and second electrode assemblies each comprising a bounding electrode, an end portion of said drift electrode member and a central electrode intere posed between said bounding electrode and the respective end portion of said drift electrode member, a transmission line coupling said velocity-control electrode assembly to said second electrode assembly, said transmission line comprising a tubular conductor and another conductor within said tubular conductor, said first and second cavity resonators being constituted by a cylindrical, solid, conducting member having cavities at each end connected by a central bore constituting said drift electrode member and a second bore constituting said outer tubular conductor of said transmission line through which said inner conductor passes, the outer portion of said solid member forming a portion of said envelope, said third electrode assembly comprising two bounding electrodes in opposing walls of said third cavity resonator, said first, said second and said third cavity resonators being adjacent the path of said electron beam, and output electrode means arranged in said third cavity resonator.

14. An electron discharge tube as claimed in claim 13 wherein that portion of said envelope beyond said first and second cavity resonators is composed of insulating material and said third cavity resonator surrounds said envelope.

15. An electron discharge tube as claimed in claim 13 wherein said third cavity resonator is provided with an adjustable member constituting one of said bounding electrodes and forming tuning means for said third cavity resonator.

16. An electron discharge tube for generating oscillations comprising, an envelope and within said envelope, a heater, a cathode, a grid, an accelerating electrode, a further electrode and a collector electrode, a first cavity resonator, a velocity control electrode assembly in said first cavity resonator, a second cavity resonator, a second electrode assembly in said second cavity resonator, a drift electrode member interposed between and coupling said velocity-control electrode and said second electrode assemblies together, the axis of said drift electrode member coinciding with the axis determined by said cathode and said collector electrode, said velocity-control and second electrode assemblies each comprising a bounding electrode, an end portion of said drift electrode member and a central electrode interposed between said bounding electrode and the respective end portion of said drift electrode member, said cavity resonators constituting a portion of said envelope and being interposed between said accelerating electrode and said further electrode, a transmission line coupling said velocity-control electrode assembly to said second electrode assembly, said transmission line comprising a tubular conductor and another conductor within said tubular conductor, said inner conductor being coupled at each end to the central electrode of the respective electrode assemblies, said first and said second cavity resonators comprising cylindrical drums having axes parallel to. the axis of said 2,508,816 j v 9 10 drift electrode member, the outer conductor of REFERENCES CITED said transmission line terminating in said drums.

The following references are of record in the 17. An electron discharge tube as claimed in claim 16 comprising a protuberance on one of me of thls patent:

said drums adjacent one of the central electrodes 5 UNITED T T TENTS of one of said electrode assemblies and an adjustable conducting electrode capacitively coug ggg z gi pled to said central electrode and within said 2312723 Llewelly'g Mar 1943 protuberance. fl

2,317,140 GlbSOIl Apr. 20, 1943 ggggggiggfiggfig- 2,368,031 Llewellyn Jan. 23, 1945 2,406,370 Hansen et a1. Aug. 27, 1946 FRAN S NIICHEL PENNING. 

